# CVE-2026-88265: crun symlink following in /dev/null leads to host file access

Source: https://junglewise.ai/threats/cve-2026-88265-crun-symlink-following-in-dev-null-leads-to-host-file-access  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-10. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-88265 · Severity: medium · CVSS 5.6 · Published 2026-09-10

crun is a lightweight container runtime used to execute containerized applications. A flaw allows a malicious container to replace /dev/null with a symlink, which after the container is isolated (pivot_root), enables the container process to attach a host file to its stdin/stdout/stderr and change that file's ownership. This could allow an attacker to modify or compromise host system files from within a container.

Technologies: [Containers Crun](https://junglewise.ai/threats/technologies/crun). Vendors: [Containers](https://junglewise.ai/threats/vendors/containers).

## Quick answers

**Is CVE-2026-88265 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-88265 being exploited in the wild.

**How severe is CVE-2026-88265?** Medium severity, with a CVSS score of 5.6, published 10 September 2026.

**Which products and versions are affected?** Containers Crun 1.29.1 and earlier.

**Is there a fix for CVE-2026-88265?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-88265 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-88265?** Check whether you run Containers Crun at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a link-following flaw (CWE-59) in crun's stdio reopening logic. After pivot_root, crun attempts to reopen /dev/null for stdin/stdout/stderr; if a container has replaced /dev/null with a symlink pointing to a bind-mounted host file, the symlink is followed, attaching the host file to the container's stdio. The attacker can then modify the file's ownership. Attack vector is local with low privilege requirement and high complexity (requires a malicious container image and specific /dev setup). Default configurations mounting a fresh /dev are not vulnerable. No patch is currently available.

## Affected products

- containers crun 1.29.1 and earlier

## Timeline

- 2026-09-10: disclosed

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-88265](https://access.redhat.com/security/cve/CVE-2026-88265)

## Related threats

- [crun terminal setup path redirection vulnerability](https://junglewise.ai/threats/cve-2026-88264-crun-terminal-setup-path-redirection-vulnerability)
- [crun privilege escalation in libkrun with passt networking](https://junglewise.ai/threats/cve-2026-84042-crun-privilege-escalation-in-libkrun-with-passt-networking)